The problem stems from the fact that only a handful of reactors around the world manufacture molybdenum-99, the precursor to technetium-99m. The current situation - in which three of these reactors, including the Petten site, are out of action due to maintenance work - means that hospitals are facing a shortage of radioisotopes and patients are having to wait longer for nuclear-medicine procedures.

But this insecurity could be a thing of the past, according to claims from Bert Wolterbeek of the Reactor Institute Delft, part of Delft University of Technology in the Netherlands. Writing in the university journal Delta, he explains that the current technetium-99m manufacturing process uses enriched uranium, a material that requires a special permit due to nuclear non-proliferation treaties.

Wolterbeek is working on a radical solution to this obstacle: developing a method for producing technetium-99m without uranium. If his work proves applicable in an industrial environment, many more factories could manufacture the sought-after isotope - considerably reducing the risk of shortages.

"Technetium-99m, the material in question, is currently made by highly enriched uranium fission," he explained. "One of the products created is radioactive molybdenum-99, the raw material for technetium-99m. Manufacturers supply this to hospitals secured in rods and a hospital can 'harvest' the technetium-99m isotope from a rod for a week as the molybdenum-99 slowly decays into technetium-99m."

Molybdenum-99 can, however, also be manufactured directly from molybdenum-98. This stable isotope is made of natural molybdenum, a material that mining companies already extract from the ground. Wolterbeek has patented a technique in which he bombards this raw material with neutrons in order to make molybdenum-99.

The molybdenum atoms are not just "activated" by the neutron bombardment, but are separated from the surrounding atoms by the energy transfer. The resultant molybdenum-99 can then be dissolved in water, which means that it can be produced in highly concentrated form. Wolterbeek says that this aspect is crucial. "The activity concentration of the radioactive material needs to be high, otherwise patients will be given too high a chemical dose to form a clear radiation image," he explained.

Wolterbeek now hopes to hold larger-scale tests in conjunction with UK reprocessing company Urenco. According to Charles Mol, head of Urenco's Stable Isotopes department, scientists around the globe are searching for alternative manufacturing methods in anticipation of the point at which nuclear non-proliferation treaties will prohibit the use of enriched uranium.

Mol continued: "Another reason is that the current manufacturing process produces a huge amount of radioactive waste. And any alternative method using low-enriched uranium could produce even more waste."